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百变干细胞

环球科学 2024年第10期 52-55页

作者：劳拉·沃克戴黛(译) 不详

干细胞是我们身体中所有细胞的“母细胞”,是构建人体的基石。不管是脚底的皮肤细胞,还是眼睛中的感光细胞,干细胞可以分化为身体内任何类型的细胞。早在1902年,就有一些科学家提出人体中存在着干细胞,但是直到1978年,科学家才在脐带血... 详细信息

干细胞是我们身体中所有细胞的“母细胞”,是构建人体的基石。不管是脚底的皮肤细胞,还是眼睛中的感光细胞,干细胞可以分化为身体内任何类型的细胞。早在1902年,就有一些科学家提出人体中存在着干细胞,但是直到1978年,科学家才在脐带血中发现了干细胞。自此,干细胞迅速成为了科学界和媒体关注的焦点。由于干细胞能够被引导分化为任何类型的细胞,取代那些受损或死亡的细胞,人们纷纷猜测干细胞也许能够帮人类治疗类似阿尔茨海默病之类的疑难杂症,也许还能培育出各种完整的新器官。

关键词：阿尔茨海默病干细胞感光细胞皮肤细胞疑难杂症脐带血母细胞媒体关注

Poly(ADP-ribose),adherens junctions,vinculin and the actin cytoskeleton:Current evidence,future perspectives and implications

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BIOCELL 2022年第12期46卷 2531-2535页

作者： laura LAFON-HUGHES Instituto de Investigaciones Biológicas Clemente Estable Ministerio de Educación y CulturaMontevideo11600Uruguay Centro Universitario Regional Litoral Norte Universidad de la RepúblicaSalto50000Uruguay

Poly(ADP-ribose)(PAR)is a highly negatively charged *** is synthesized by poly(ADP-ribose)polymerases(PARPs)and is involved in the assembly and stabilization of macromolecular ***,the presence and putative roles of poly(ADP-ribosyl)ation(PARylation)associated to adherens junctions(AJ)and the actin cytoskeleton in epithelial and Schwann cells,is *** hypothesis generated by analogy,stating that PAR is associated to AJ in other cell types,is *** to this hypothesis,PAR associated to puncta adherentia in chemical synapses would participate in plasticity,learning and *** turn,PAR associated to fascia adherens in cardiomyocytes,would affect heart *** inhibitors are currently under development and clinical *** research in different tissues will probably influence their clinical uses.

关键词： PARP Tankyrase Epithelia Neuron Schwann cell Cardiomyocyte Vinculin

Tree species richness enhances stand productivity while stand structure can have opposite effects, based on forest inventory data from Germany and the United States of America

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Forest Ecosystems 2018年第1期5卷 36-52页

作者： laura Zeller Jingjing Liang Hans Pretzsch Center of Life and Food Sciences Weihenstephan Technical University of MunichHans-Carl-von-Carlowitz-Platz 285354 FreisingGermany Division of Forestry and Natural Resources Davis College of AgricultureNatural Resources&DesignWest Virginia University340 Percival HallMorgantownWV 26506-6108USA

Background： in recent studies, mixed forests were found to be more productive than monocultures with everything else remaining the same. Methods： To find out if this productivity is caused by tree species richness, by a more heterogeneous stand structure or both, we analyzed the effects of forest structure and tree species richness on stand productivity, based on inventory data of temperate forests in the United States of America and Germany. Results： Having accounted for effects such as tree size and stand density, we found that：（I） tree species richness increased stand productivity in both countries while the effect of tree size heterogeneity on productivity was negative in Germany but positive in the USA; （11） productivity was highest at sites with an intermediate amount of precipitation; and （111） growth limitations due water scarcity or low temperature may enhance structural heterogeneity. Conclusions： In the context of forest ecosystem goods and services, as well as future sustainable forest resource management, the associated implications would be：

关键词： Big data Overyielding Tree size heterogeneity Tree species mixing Climate Biodiversity-productivityrelationship

Necrotizing Pneumonia and Conservative Treatment: A Case Report and Review of the Literature

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Open Journal of Respiratory Diseases 2024年第3期14卷 69-76页

作者： Pedro Rogerio Magalhães Braga Eduarda Kipper Beck Carolina de Mello Viera Cecília Gatti Wolff laura Gazal Passos Guilherme Bastos de Mello Luis Felipe Pilar Gomes Giacomo Farias Tramontin Taíse Rosa de Carvalho Department of Internal Medicine Hospital So Lucas da PUCRS Porto Alegre Brazil School of Medicine Pontifcia Universidade Catlica do Rio Grande do Sul Porto Alegre Brazil Department of Radiology Hospital So Lucas da PUCRS Porto Alegre Brazil

We present a case of necrotizing pneumonia in an 87-year-old man without severe respiratory instability. Clinical suspicion arose due to the need for supplementary oxygen and persistent fever during treatment for community-acquired pneumonia. The diagnosis was confirmed by chest computed tomography. Although necrotizing pneumonia typically requires major surgical intervention upon diagnosis, we chose conservative management with antimicrobials and chest drainage alone. The patient experienced significant improvement and resolution of pneumonia with conservative management.

关键词： Respiratory Tract Infections Lung Disease Bacterial Pneumonia

Infertility treatment, a matter of a lovely sperm？

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Asian Journal of Andrology 2013年第6期15卷 719-720页

作者： laura C Giojalas Centro de Biologfa Celular y Molecular & Instituto deInvestigaciones Biol6gicas y Tecnol6gicas (CONICET-Universidad Nacional de Cordoba) Av. Velez Sasrfield1611 X5016GCA - Cordoba Argentina

Nowadays, the efficiency of the infertil-ity treatment is relatively low. One of the cues to counteract this problem relies on the optimum selection of spermatozoa. We developed a new method （sperm selection assay （SSA）） based on the chemical attrac-tion of spermatozoa that are at the best functional state. Additionally, the SSA leads spermatozoa to complete and/or acquire the competence to fertilize the egg. These effects are equally observed either in nor-mal or subfertile semen samples. Those cap-abilities of SSA may improve the success of current infertility treatment.

关键词： GUIDANCE

Discovering plasticity models without stress data

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npj Computational Materials 2022年第1期8卷 857-866页

作者： Moritz Flaschel Siddhant Kumar laura De Lorenzis Department of Mechanical and Process Engineering ETH Zürich8092ZürichSwitzerland Department of Materials Science and Engineering Delft University of Technology2628 CDDelftThe Netherlands

We propose an approach for data-driven automated discovery of material laws,which we call EUCLID(Efficient Unsupervised Constitutive Law Identification and Discovery),and we apply it here to the discovery of plasticity models,including arbitrarily shaped yield surfaces and isotropic and/or kinematic hardening *** approach is unsupervised,i.e.,it requires no stress data but only full-field displacement and global force data;it delivers interpretable models,i.e.,models that are embodied by parsimonious mathematical expressions discovered through sparse regression of a potentially large catalog of candidate functions;it is one-shot,i.e.,discovery only needs one *** material model library is constructed by expanding the yield function with a Fourier series,whereas isotropic and kinematic hardening is introduced by assuming a yield function dependency on internal history variables that evolve with the plastic *** selecting the most relevant Fourier modes and identifying the hardening behavior,EUCLID employs physics knowledge,i.e.,the optimization problem that governs the discovery enforces the equilibrium constraints in the bulk and at the loaded boundary of the *** promoting regularization is deployed to generate a set of solutions out of which a solution with low cost and high parsimony is automatically *** virtual experiments,we demonstrate the ability of EUCLID to accurately discover several plastic yield surfaces and hardening mechanisms of different complexity.

关键词： stress plasticity selecting

Polycaprolactone/mesoporous silica MCM-41 composites prepared by in situ polymerization

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Particuology 2017年第1期15卷 135-143页

作者： laura Lopez-Figueras Nuria Navascues Silvia Irusta Department of Chemical Engineering Nanoscience Institute of Aragon (INA) University of Zaragoza 50018 Zaragoza Spain Networking Research Center on Bioengineering Biomaterials and Nanomedicine CIBER-BBN 50018 Zaragoza Spain

Composites of polycaprolactone （PCL） with mesoporous silica MCM-41 and N-[3- （trimethoxysilyl）propyl]-ethylenediamine （EPTES）-functionalized MCM-41 （EPTES/MCM-41） were prepared by in situ polymerization. The thermal properties of the composites were characterized by thermogravimetric analysis. There was an increase in the thermal decomposition temperature of PCL by more than 55 ℃, when the EPTES/MCM-41 loading was higher than 2 wt%. Tensile test results indicated that adding MCM-41 increased the brittleness of the PCL matrix, while adding 8 wt% of EPTES/MCM-41 increased the Young＇s modulus by 26%. Incorporating MCM-41 increased the crystallinity of the resulting PCL composite, compared with that of PCL. Incorporating up to 5 wt% EPTES/MCM-41 slightly reduced the crystallinity of PCL. The different effects of MCM-41 and EPTES/MCM-41 on the composite reflected the degree of interaction and dispersion of the silica filler in the polymer matrix, as evidenced by results from transmission electron microscopy and atomic force microscopy.

关键词： Nanocomposite Mesoporous silica Polycaprolactone

Current status and trends of carbon-based electrodes for fully solution-processed perovskite solar cells

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Journal of Energy Chemistry 2022年第5期31卷 222-246页

作者： laura MGonzález Daniel Ramirez Franklin Jaramillo Centro de Investigación Innovacióny Desarrollo de MaterialesCIDEMATFacultad de IngenieríaUniversidad de Antioquia UdeACalle 70 No.52-21Medellín 050010Colombia

Perovskite solar cells(PSCs) have revolutionized photovoltaic research. As a result, a certified power conversion efficiency(PCE) of 25.5% was recorded in late 2020. Although this efficiency is comparable with silicon solar cells;some issues remain partially unsolved, such as lead toxicity, instability of perovskite materials under continuous illumination, moisture and oxygen, and degradation of the metallic counter electrodes. As an alternative to tackle this last concern, carbon materials have been recently used, due to their good electrical and thermal conductivity, and chemical stability, which makes them one of the most promising materials to replace metallic counter electrodes in the fabrication of PSCs. This review highlights the recent advances of carbon-based PSCs, where the carbon electrode(CE) is the main *** have become very promising candidates for PSCs;they are mainly fabricated using a simple combination of graphite and carbon black powders embedded in a binder matrix, giving a paste that is then solution-processable, resulting in devices with improved quality stability, when compared to metallic electrodes. In this review, CE’s composition is emphasized, since it can give both, high and lowtemperature processed electrodes, compatible with different device configurations. Finally, the tendencies and opportunities to use CE in PSCs devices are presented.

关键词： Perovskite solar cells Carbon electrodes Scaling up Stability Solution processing

Applying Gregory Johnson’s Concepts of Scalar Stress to Scale and Information Thresholds in Holocene Social Evolution

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Journal of Social Computing 2022年第1期3卷 38-56页

作者： laura J.Ellyson the Department of Anthropology Washington State UniversityPullmanWA 99163USA Terrestrial Archaeology Division SEARCH Inc.PensacolaFL 32503USA.

Although Gregory Johnson’s models have influenced social theory in archaeology,few have applied or built upon these models to predict aspects of social organization,group size,or *** have been limited to small case ***,the relationship between a society’s scale and its information-processing capacities has been explored using the Seshat ***,I apply multiple-linear regression analysis to the Seshat data using Turchin and colleagues’9“complexity characteristics”(CCs)to further examine the relationship between the hierarchy CC and the remaining 8 CCs which include both aspects of a polity’s scale and aspects of what Kohler et ***“collective computation”.The results support Johnson’s ideas that stratification will generally increase with increases in a polity’s scale(population,territory);however,stratification is also higher when polities increase their developments in information-processing variables such as texts.

关键词： hierarchy scalar stress Seshat Databank multiple imputation multiple regression